Piston expander



Sept. 12, 1939. D. D. WILLIAMS PISTON EXPANDER Filed Nov. 2, 1938PIC-3.2

FIG.5

INVENTOR. DAVID D. WILLIAMS ATTORNEY.

Patented Sept. 12, 1939 UNITED STATES P.ATENT OFFiCE '7 Claims.

This invention relates to expanding devices and particularly to devicesfor expanding pistons for internal combustion engines and the likewherein such pistons have a split skirt,

It is an important object of my invention to provide a device of thischaracter adapted to resiliently expand the skirt of pistons having saidskirt longitudinally split'or slotted.

It is another object of my invention to provide a device of thischaracter wherein the expanding means is securely held chordally withinthe piston across the split or slot.

Another object of the invention is to provide a device of this characterhaving rivets against which the expanding spring acts, said rivets beingsecurely fixed in openings therefor in the skirt on opposite sides ofthe slot and having heads thereon for retaining the spring in place.

A further object of the invention is to provide simple means for lockingsame in adjustable positions, said device being adjustable for tension.

Still another object of the invention is to pro.- vide locking meanstherefore which will not injure the threads of the adjustment screw.

A still further object of the invention is to provide a device of onesize which will fit substantially all alloy pistons thereby simplifyingmanufacturing and marketing of said device.

. Numerous other objects and advantages of the invention will beapparent as it is better undenstood from the following description,which, taken in connection with the accompanying drawing, discloses apreferred embodiment thereof. Referring to the drawing:

Figure 1 is a vertical section through a piston embodying the inventiontaken on line -I of Figure 2.

Figure 2 is a horizontal section through a piston embodying my inventiontaken on line 2-2 piston generally having a skirt II which is obliquelysplit or slotted at [2.

My expansion device comprises a generally octagonal expansion spring 13,oppositely disposed sides !4 of which are concave and .are 5 adapted tobe engaged with rivets which are secured in openings in the skirt H onopposite sides ofthe slot It. The rivets are preferably of brass orother relatively soft metal so that the ends which extend to the outsideof the piston will not score the walls of a cylinder in which the pistonoperates. The axis of each rivet is substantially radial with respect tothe circumferential center of the piston and the sides of the bodyportion l6 of said rivets are tapered inwardly toward the head withrespect to the longitudinal centers of said rivets to compensate for theangularity of the axes thereof. A head l5 on each rivet retains theexpansion spring from movement longitudinally of said rivets. ,Side H ofspring 53 is provided with an opening l8 ,therethrough adjacent thecenter thereof in which an adjustment screw 19 is received, the head ofsaid screw having a slot for reception of a screw-driver or otherinstrument for turning same. 7

The free ends 20 of the spring i3 are turned longitudinally with respectto screw l9 and are partially curved about the screw to provide greatercontact surface with said screw. The free end of the screw I9 isprovided with a nut 21] having a diametrically extending slot 22 in oneend adapted to receive the free ends 20 of the spring therein when thenut is screwed onto the screw IS. The free ends 2fl of the spring, whenextending into the slot 2!] of nut 2| retain said nut against rotationwith respect to the screw l9 thereby permitting the nut to be screwedfurther onto the screw, which action draws the free ends it and side I!toward each other and causing sides M to be forced apart, said sidesexerting separating pressure on the respective rivets thereby effectingexpansion of the skirt. The pressure of spring I3 is sufiicient toovercome the resiliency of the skirt under normal conditions althoughthe spring has a certain amount of inherent resiliency. Adjustment ofthe screw l9 effects the desired expansive pressure for properfunctioning of the piston in its cylinder.

The slot 22 in nut 2| is so formed that as said nut is drawn onto thescrew is the'free ends 20 of the spring 13 are pressed against the screwto normally frictionally retain the screw l9 against rotation. The screw[9 is preferably case hardened to prevent undue wearing of the threadswhich come into contact with the free ends 20 of the spring. It will bereadily apparent that this device may be constructed in one size whichis adapted to fit substantially all sizes of pistons.

The invention is particularly adapted for use with pistons of the hereindescribed character wherein the skirt has become worn through use and istoo loose in the cylinder. The expander is adjusted to expand the pistonskirt to the proper size for proper operation in its cylinder.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description and it will beapparent that various changes may be made in the form, construction, andarrangement of the parts without departing from the spirit and scope ofthe invention or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

Having thus described my invention what I claim is:

1. In a device of the class described, the combination of a pistonhaving a slotted, expansible skirt, comprising a rivet fixed in openingstherefor in the skirt on opposite sides of the slot thereof, the axes ofsaid rivets being substantially radial with respect to thecircumferential center of the piston, a head on the free end of eachrivet, the sides of the body of said rivets being tapered inwardlytoward the head with respect to the axes thereof to provide relativelyparallel sides for said rivets with respect to each other, asubstantially flat spring generally octagonally shaped in longitudinalcross-section and having the free ends thereof adjacent each other insubstantially parallel relationship, said spring having an opening inthe side opposite the free ends thereof, a screw received in saidopening and received between the free ends of said spring, said freeends being laterally curved about the screw, and a nut adapted to bescrewed onto said screw, said nut having a diametrical slot in one endin which the free ends of the spring are received to provide frictionalpressure of said free ends on the screw, said nut being retained againstrotational movement on the screw by said free ends, said spring havingconcave portions on opposite sides of the screw, said spring beingdisposed between the rivets which are received in the concave portionsof said sides, and being retained in position by the heads of the rivetswith respect to longitudinal movement on said rivets.

2. In a device of the class described, the combination of a pistonhaving a slotted, expansible skirt with an expanding device comprising arivet fixed in openings therefor in the skirt on opposite sides of theslot thereof, a fiat spring, substantially octagonal in longitudinalcrosssection and having oppositely disposed sides concave, said springbeing received between the rivets and said rivets contacting the concavesides of said spring, the laterally extending sidelof the spring havingan opening therein, a screw received in said opening and extendinglongitudinally of said spring, the free ends of said spring being turnedlongitudinally outwardly in substantially parallel relationship withsaid. screw, said screw extending between said free ends of the spring,the latter being partially curved about said screw, a nut having a slotin one end adapted to receive the free ends of the spring therein and toefiect frictional pressure of said free ends on the screw when said nutis drawn onto said screw, and a head on each rivet adapted to preventmovement of the spring longitudinally of said rivets.

3. In a device of the class described, the combination of a pistonhaving a slotted, expansible skirt with an expanding device comprising aflat spring, substantially octagonal in longitudinal cross-section andhaving the free ends thereof adjacent each other in substantiallyparallel relationship, said spring having an opening in the sideopposite the free ends thereof, a screw received in said opening andbetween the free ends of said spring, said free ends being laterallycurved about the screw, a nut on the screw having a slot in one end inwhich is received said free ends, a rivet on each side of the slot ofthe skirt, said rivets being within the piston and secured to the skirt,said spring being disposed between the rivets with the screw extendingsubstantially longitudinally of the length of the piston, and means forretaining the spring between the rivets.

4. In a device of the class described, the combination of a pistonhaving a slotted, expansible skirt with a resilient expanding devicecomprising a fiat spring having an opening adjacent the longitudinalcenter thereof, a screw received in said opening, said spring beingturned longitudinally'of said screw with opposite sides spacedtherefrom, the free end portions of said spring being in substantiallyparallel relationship with each other and being laterally curvedpartially about the screw, a nut on the screw, said nut having a slot inone end adapted to receive the free ends of the spring and impartpressure thereto whereby said free ends frictionally grip the screw whenthe nut is drawn further onto the screw, opposite sides of the springbeing simultaneously forced outwardly with respect to said screw, and alug on each side of the slot of the skirt of the piston and secured tosaid skirt, said spring being disposed between said lugs and adapted toexert expansive pressure thereto when the sides of the spring are forcedoutwardly by tightening the nut on the screw.

5. In a device of the class described, the combination of a pistonhaving a slotted expansible skirt with an expanding device comprising aflat spring having an opening adjacent the longitudinal center thereof,a screw rotatably received in said opening, said spring being turnedlongitudinally of said screw with opposite sides spaced therefrom, thefree end portions of said spring being in substantially parallelrelationship with each other, with the screw received between them, anut on the screw, said nut having a slot in one end adapted to receivethe free ends of the spring whereby pressure is imparted to said ends toeffect a friction grip of said ends on said screw when the nut is drawntight on said screw, opposite sides of the spring being simultaneouslyforced outwardly with respect to the screw, and a lug on each side ofthe slot of the skirt and secured thereto, said lugs being within thepiston, said spring being disposed between said lugs and adapted toexert expansive pressure thereon when the sides of the spring are forcedoutwardly by tightening the nut on the screw.

; 6. An expanding device adapted to be operably attached to a pistonhaving an expansible slotted skirt, said device comprising a relativelyfiat spring substantially octagonal in longitudinal cross-section andhaving the free end'portions adjacent each other in substantiallyparallel relationship, said spring having an opening in the sideopposite the free ends, a screw received in said opening and extendingbetween the free end portions, the latter being laterally curvedpartially about the screw, and a nut on the screw, said nut having aslot in one end adapted to receive the free ends of the spring therein.

7. An expanding device adapted to be operably attached to a pistonhaving an expansible slotted skirt, said device comprising asubstantially flat spring having an opening adjacent the longitudinalcenter thereof, a screw operably received in said opening, said springbeing turned longitudinally of said screw with opposite sides spacedment of the sides of the spring with respect to 10 the screw.

DAVID D. WILLIAMS.

